Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Multi-Way Conventional loudspeakers with crossovers

Air displacement
Air displacement
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 13th June 2018, 07:25 PM   #11
TBTL is offline TBTL  Germany
diyAudio Member
 
Join Date: Oct 2013
What do you mean?
  Reply With Quote
Old 13th June 2018, 08:00 PM   #12
Shure is offline Shure  Sweden
diyAudio Member
 
Join Date: May 2010
Moving more air means more bass right?
  Reply With Quote
Old 13th June 2018, 08:34 PM   #13
KaffiMann is offline KaffiMann  Norway
Fanatic
diyAudio Member
 
KaffiMann's Avatar
 
Join Date: Sep 2009
Location: Grua, not far from Oslo.
Air displacement
Allright. At the risk of repeating stuff you may already know:
Part of the reason why a proper well designed Bass Reflex works, is that the resonant behaviour of the vent coupled with the internal volume of the box, at specific frequencies, sort of reflect forces that again work against the drivers movement. If it was a closed box, the movement of the driver at a specific power level would increase the lower the frequency.
With the Reflex box, the reflective forces will eventually be greater than the movement of the driver, until eventually the vent does not cause resonant behaviour at even lower frequencies, and the driver has further increased excursion than it would if it was a closed box. IE, at a low enough frequency, the vent creates all the sound, not the driver. But below this frequency again, there is no gain.

With a BR design, you are just pushing the point of increased excursion lower in frequency.

At the very basics, yes, moving more air equals more bass. But it depends heavily on type of enclosure and size of enclosure. As a general rule, a big box will make more bass at the same power level than a small box, but this again, depends on the properties of the driver chosen for the design.
Also, a big driver with low xmax but high surface displacement has the potential for lower distortion than a small driver with higher xmax but low surface displacement, even if the potential for moving air is equal. Another thing to consider, is force cancelation, if you have opposing woofers on each side or front/back of an enclosure, they have the potential to cancel each others vibrational forces, further reducing unwanted effects.

Last edited by KaffiMann; 13th June 2018 at 08:36 PM.
  Reply With Quote
Old 14th June 2018, 10:12 AM   #14
giralfino is offline giralfino  Italy
diyAudio Member
 
giralfino's Avatar
 
Join Date: Feb 2009
Quote:
Moving more air means more bass right?
The short answer is no. Comparing 2 drivers, if at a specific frequency one moves more air than the other, then you can conclude that it has more SPL capability at that specific frequency alone only if the drivers have the same efficiency (i.e. same base SPL), and only if they are in a closed box.

Quote:
What im thinking is that choosing one woofer over another only becouse it can play lower doesn't mean it will play more bass but the air displacement must be taken into consideration aswell to get more bass?
IMHO you are approaching this in the wrong way. Air displacement doesn't mean anything in a BR box. You have to look at the combined driver+tube output and not the driver's alone. At tuning, the sound comes from the tube and not from the driver, have a look at the attached picture. If you want to compare two drivers use a decent box simulator and see what happens changing box volume and tuning frequency, those parameters will affect the bass extension and its shape. Max SPL is determined by the T/S parameters of the driver.

Ralf
Attached Images
File Type: gif test-fr.gif (41.4 KB, 26 views)
  Reply With Quote
Old 14th June 2018, 10:53 AM   #15
TMM is offline TMM  Australia
diyAudio Member
 
Join Date: Sep 2007
Location: Australia
Send a message via AIM to TMM
The Accuton system has less cone displacement because the port is doing more work at 50Hz compared to the SEAS system.

For the same SPL at the same frequency, the total air displaced (woofer cone + port) by two different systems is the same.
  Reply With Quote
Old 14th June 2018, 12:59 PM   #16
KaffiMann is offline KaffiMann  Norway
Fanatic
diyAudio Member
 
KaffiMann's Avatar
 
Join Date: Sep 2009
Location: Grua, not far from Oslo.
Air displacement
Apples and pears.
  Reply With Quote

Reply


Air displacementHide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Cone displacement Alcelaphus Subwoofers 37 25th December 2016 02:42 PM
JBL GTO1514 displacement? AndrewF Subwoofers 4 11th October 2013 11:48 PM
Volume Displacement Calculation lovitz Multi-Way 5 11th March 2007 01:52 AM
quartz displacement guytou Digital Source 5 6th May 2005 11:01 PM
driver displacement joelives Multi-Way 2 11th June 2003 06:02 PM


New To Site? Need Help?

All times are GMT. The time now is 03:37 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki